The correct option is C Palladium (Pd)
Scandium (Sc) lies in the 3rd group and 4th period
Mangenese (Mn) lies in the 7th group and 4th period
Palladium (Pd) lies in the 10th group and 5th period
Platinum (Pt) lies in the 10th group and 6th period
Metallic character increases down the group and decreases along the period.
Therefore, Palladium has the least metallic character.